(b) Active Processes: In the simulation the growth of individual particles is stochastic. They undergo division on reaching a critical radius (\(R_m=5~\mu m\) ). The growth of the \(i^{th}\)  particle is dependent on the pressure \(p_i\)  due to neighboring particles. Therefore, the growth of individual particles are micro-environment dependent. We use Irving-Kirkwood definition [1]} to calculate pressure on the \(i^{th}\)  particle,
\(p_i=\frac{1}{V_{NN(i)}+ V_i}\sum _{j=1}^{NN(i)}{\bf F}_{ij}\cdot d{\bf r}_{ij}.\) 
